Barrier layer made of a curable resin containing polymeric polyol

ABSTRACT

A component involving a substrate, a layered structure arranged on the substrate, and a barrier layer arranged over the layered structure, wherein the barrier layer has the reaction product of an epoxy resin and a polymeric polyol.

The invention relates to a component comprising a substrate and alayered structure arranged on the substrate, wherein the layeredstructure is sensitive to moisture and should be protected. In order toprotect the layered structure, the component further comprises a barrierlayer that covers the layered structure. The barrier layer is alsocalled a capping layer. As a layer that is sensitive to moisture may aswell be sensitive to corrosion, the expression ‘sensitive to moisture’is used to refer to ‘sensitive to moisture’, ‘sensitive to corrosion’,or to ‘sensitive to both moisture and corrosion’.

An example of a component to which the invention relates is a componentwherein the layered structure includes an optically or an electricallyactive thin film, such as a radiation detector, a solar cell or a solarmodule, or an optoelectronical component, such as a light emittingdisplaying device and a liquid crystal display (LCD) screen.

Among the solar cells, thin film solar cells take a particular prominentposition. Thin film solar cells represent a significant progress in thetechnology, since they can be manufactured essentially morecost-effectively than conventional solar cells. The thin film technologyis based upon the direct deposition of an absorber layer having athickness of 0.002 mm on a substrate. The layered structure furtherincludes a molybdenum back electrode on the substrate and a frontelectrode on the absorber layer. A series connection for increasing themodule voltage is integrated in the manufacturing process, and in thisway expensive soldering procedures are avoided. The absorber layer isthe layer that is sensitive to moisture. However, not only the absorberlayer is vulnerable, also the electrodes are sensitive to moisture.

A suitable thin-film absorber layer includes copper-indium-diselenide(CuInSe₂, in short: CIS). The CIS technology has particular favourableperspectives to achieve a high efficiency, good long-term stability andlow costs. A suitable substrate is float glass. The maximum efficienciesof 17 to 18% achieved are the highest among all thin film cells. Evenmore than these values, achieved in single cases with small cells,module efficiencies of up to 14% demonstrate the potential of thistechnology. Another advantage lies in the fact that the layers that canbe manufactured in large panels, are cut by lasers and automaticallyconnected to modules thereafter by the integrated series connections.

In order to meet the quality demands of the market, solar modules mustsuccessfully run through a series of different test procedures. One ofthese procedures, which should test the climate resistance of the solarmodules, is the damp-heat test. In this test the modules are exposed toa temperature of 85° C. at 85% relative air humidity for 1 000 hours,according to the known standard IEC 1215.

When a moisture-sensitive layer is subjected to moisture its sheetresistance increases, and the quality of the encapsulation determinesthe increase in sheet resistance.

The sheet resistance, ρ_(s) in ohms, is a measure of the resistance of athin layer of material looking edge-on into the layer. In equation:ρ_(s)=ρ/t, wherein t is the thickness of the layer in cm, and wherein ρis the resistivity of the material in ohms·cm, which resistivity isdefined as ρ=RA/1, wherein R is the resistance of the layer in ohms, Athe cross-sectional area of the layer in cm² and 1 the length of thelayer in cm.

Reducing the sensitivity to moisture of a component cannot be achievedby simple encapsulation with a laminate arrangement including anadhesive foil and, possibly, a second glass plate.

One possibility to avoid the diffusion of moisture into a laminatedlayered structure, in particular into a solar module, is to make thepath for moisture diffusion longer. This requires a sufficiently broadedge or rim of more than 15 cm. Such a broad edge or rim, however, isnot acceptable in a solar module, because the rim considerably reducesthe active module surface.

Another solution is disclosed in German patent application publicationNo. 197 07 280. This solution is providing an inorganic barrier layerthat is selected from the group consisting of Al₂O₃, Si₃N₄, TiN, MoN andSiO_(x)N_(y).

German patent specification No. 195 14 908 discloses a componentcomprising a substrate and a layered structure arranged on thesubstrate, and a barrier layer arranged over the layered structure,wherein the barrier layer comprises the reaction product of apolyisocyanate and a trifunctional polyol based on trimethyl propane.This is a conventional polyurethane system.

The present invention provides a component that is insensitive tomoisture, which can be manufactured more easily than an inorganicbarrier and without high additional manufacturing expenses, and whichdemonstrates an increased stability against the test conditionsdescribed above, as well as during normal operation.

To this end the component according to the present invention comprises asubstrate, a layered structure arranged on the substrate, and a barrierlayer arranged over the layered structure, wherein the barrier layercomprises the reaction product of a polymeric polyol and a curableresin, characterized in that the curable resin is an epoxy resin.

In the specification and in the claims, the expression ‘curable resin’will be used to refer to a cross-linking resin, a thermosetting resin ora vulcanizable resin.

Reference is now made to European patent application publication No. 903790. This publication discloses a component comprising a substrate and alayered structure arranged on the substrate, and a top encapsulatingmaterial arranged over the layered structure, wherein the topencapsulating material comprises polyolefin-based resins, such asethylene-vinyl acetate copolymer, ethylene-methylacrylate copolymer,ethylene-ethylacrylate copolymer, and polyvinyl butyral resin, urethaneresin, silicone resin and fluororesin. The bottom encapsulating materialcomprises ethylene-vinyl acetate or polyvinyl butyral.

Reference is further made to U.S. Pat. No. 6,204,443. This publicationdiscloses a component comprising a substrate and a layered structurearranged on the substrate, and a surface side filler arranged over thelayered structure, wherein the surface side filler comprises a layer ofa non-cross-linked polymer resin (ethylene-vinyl acetate copolymer,polyvinyl butyral, epoxy resins, acrylic resins, silicone resins andfluoro resins) that is sandwiched between two layers of a cross-linkedresin. The cross-linking agent is an isocyanate, a melamine or anorganic peroxide.

Moreover, reference is made to U.S. Pat. No. 6,288,326. This publicationdiscloses a component comprising a substrate and a layered structurearranged on the substrate, and an encapsulation arranged over thelayered structure, wherein the encapsulation comprises ethylene-vinylacetate and polyisobutylene resin.

The invention will now be described by way of example in more detailwith reference to the accompanying drawings, wherein

FIG. 1 shows schematically and not to scale a cross-section of acomponent according to the present invention;

FIG. 2 shows the structural formula of polyvinyl butyral;

FIG. 3 shows the reaction of polyvinyl butyral with an epoxy resin; and

FIG. 4 shows schematically and not to scale cross-section through acomponent that was used in test.

Reference is now made to FIG. 1. The component according to the presentinvention comprises a substrate 1, on which is deposited a layeredstructure 2. The layered structure includes a back electrode 3 depositedon the substrate 1, an absorber layer 4 deposited on the back electrode3 at least one front electrode 5 arranged on the light-receiving surfaceof the absorber layer 4.

The component according to the present invention further includes abarrier layer 7 comprising the reaction product of a curable resin and apolymeric polyol. The barrier layer 7 extends over the outer surface ofthe layered structure 2 and ends on rims 8 of the substrate 1. Thethickness of the barrier layer is suitably in the range of from 100 nmto 2 mm.

To complete covering the component a conventional laminate is applied.The laminate consists of a cover 10 of transparent glass 12 and anadhesive layer 11, by which the laminate is adhered to the barrier layer7. The adhesive layer 11 is suitably a layer consisting of polyvinylbutyral having a thickness of 0.5 mm. The laminate is applied at atemperature of 150° C.

For the sake of simplicity we did not show the electric contacts thatare attached to the back electrode 3 and the front electrode 5 to carryaway the current generated during normal operation.

The way in which the barrier layer is formed from a liquid resincomposition containing a curable resin and a polymeric polyol isdiscussed at a later stage.

The barrier layer according to the present invention is not onlymoisture proof, but also it adheres so well to the substrate thatdiffusion of moisture along the interfaces at the rims 8 between thesubstrate 1 and the barrier layer 7 is prevented. Applicant had foundthat diffusion of moisture through the barrier layer itself wasinsignificant as compared to diffusion of moisture along the interfacesbetween the barrier layer and the substrate.

The barrier layer according to the present invention comprises thereaction product of a curable resin and a polymeric polyol. The barrierlayer is obtained by applying a liquid resin composition containing thecurable resin and the polymer polyol on the surfaces of the component tobe covered, and then allowing the polymer polyol to react with theresin.

Application of the liquid resin composition can be done by spraying,brushing, dipping, and a spin on method, screen printing and so on.

For application the liquid resin composition can further be diluted witha solvent, for example for spraying or brush application, withethoxypropyl acetate.

After application of the liquid resin composition, the reaction betweenthe polymeric polyol and the curable resin is allowed to proceed.

The polymeric polyol is a higher molecular polyol, in particular with amolar mass of about 1 000 or higher. Examples of the polymeric polyolare polyvinyl alcohol, a polyester- and/or a polyether polyol.

A particularly suitable polymer polyol is polyvinyl butyral (PVB) ofwhich the structural formula is shown in FIG. 2, which has free hydroxylgroups. Depending on m, n, o, different physical and chemical propertiesare achieved. The molar mass or the degree of polymerisation,respectively, exhibits great importance for the thermal and mechanicalproperties and for the viscosity in solution.

The polymeric polyol can as well be a mixture of the above-mentionedexamples of polymeric polyols.

The second component is a curable resin in the form of an epoxy resin.The second component can as well be a mixture of an epoxy resin and anisocyanate.

The reaction between the polymer polyol and the curable resin, is calledhardening, setting or cross-linking. If a solvent is present, thereaction is started after flashing off the solvent. The reaction iscarried out by ultra violet (UV) radiation treatment, for example with acommercially available mercury discharge lamp.

The reaction of polyvinyl butyral with an epoxy resin is shownschematically in FIG. 3.

The curable resin is an epoxy resin. The epoxy resin incorporated in thebarrier layer can be an aliphatic, cycloaliphatic or aromatic epoxide,with aliphatic and cycloaliphatic, i.e. ring epoxidised, epoxides beingpreferred. Advantageously, the epoxy resin consists of ≧70% by weight ofan aliphatic and/or cycloaliphatic epoxide.

In particular, epoxidised polybutadiene or epoxidised soy bean oil isthe aliphatic epoxide; further usable epoxides are, for example,dodecene oxide and diglycidyl ester of hexahydrophthalic acid. Thecycloaliphatic epoxides are preferably diepoxides. Such diepoxides are,for example, 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexanecarboxylate(EEC) and bis (3,4-epoxycyclohexylmethyl)adipate. Other such epoxidesare for example compounds where the aliphatic chain of the adipic acidderivative, consisting of 4 methylene units, is substituted by a chainwith 5 to 15 methylene units.

The underlying hardening chemistry is the cationic polymerisation ofepoxy resins and the copolyaddition with suitable polyhydroxylcompounds. PVB is a hydroxyl compound of that kind and therefore ischemically incorporated or participates in the cross-link formation ofthe resulting high quality moulding material. The resulting mouldingmaterial is duroplastic, shows a good adhesion and demonstrates goodtensile strength and elasticity. Furthermore it has a good lighttransmitting capacity, which makes it especially suitable for the use insolar cells and light emitting components.

By means of the capability to trigger the cross-linking by UV light aquick hardening of the lacquer layer is possible. The hardening is nottriggered purely thermally, so that the formulations have an almostunlimited usable life, when short wave light is excluded. This providesflexibility for the application process and facilitates the automationof the latter. Normally neither vacuum nor a high temperature process isnecessary for application and hardening. Only for the acceleration offlashing off a possibly present solvent and for the acceleration of thefinal hardening after exposure to UV, a slight increase of thetemperature may be useful.

The PVB containing curable resin is exposed to UV light by means of alamp or of a laser at a wavelength that preferably corresponds to theabsorption of the photoinitiator contained in the curable resin. In theexemplary case the exposition is done with a mercury discharge lamp witha power density of 100 mW/cm² within the UV A range, at an radiationperiod of 20 seconds. By means of a following thermal treatment at 60°C. for the duration of 20 minutes the barrier effect against water andoxygen is additionally improved.

A suitable liquid resin composition for the barrier according to thepresent invention contains epoxy compounds, particularly diepoxides (30to 95% by weight of the composition), polyvinyl butyral, suitably 1 to15% by weight of the composition, and photoinitiators. Optionally alsolacquer additives like antifoaming agents, levelling agents and/oradhesion promoting agents can be contained. Depending on the applicationprocess, they can additionally contain solvents, which are flashed offprior to an UV hardening.

Depending on the OH group contents, PVB is further cross-linked withother reaction partners. In practical use, reactants like epoxy resins,phenol resins and melamine resins are used. For other applicationscorrespondingly catalysed phenol carbamide resins or melamine resins,and polyisocyanates and dialdehydes can be used as co-reactants. Athermal hardening also can take the place of UV hardening here.

By the special, cationically initiated hardening of the curable resin,i.e. the UV hardening, to a certain extent ‘one’ polymeric molecule isobtained, which is free from low molecular degassable components whichimpair the capacity of the component to be protected. Advantageously athermal treatment, preferably up to a temperature of 120° C., can followthe UV hardening. In general, the lower temperature limit lies at 10 to20° C. below the glass-transition temperature of the hardened curableresin. By means of the thermal treatment (post-hardening) the barriereffect of the barrier layer against water and oxygen can be furtherincreased.

In particular, the resin is UV-curable, i.e. it sets under the influenceof UV light. In the present application UV curable epoxy resins areparticularly suitable.

The amount of polymeric polyol is suitably more than 1% by weight of thecurable resin, in particular more than 5% by weight. Preferably theamount of polymeric polyol proportion is in the range of from 1% byweight to 15% by weight of the curable resin, but can be up to 30% byweight of the curable resin.

The barrier layer preferably consists almost completely of the reactionproduct of the curable resin and the polymeric polyol.

The barrier layer may be applied in known procedures as an impermeablelayer, i. e. being free from pores, optically transparent and edgecovering. Depending on the impermeability or freeness from pores such alayer is manufactured with a barrier layer having a thickness of 1micrometre can already be sufficient to ensure a sufficient protectionagainst moisture. Of course, a thicker barrier layer is possible. Forapplication processes where barrier layers are obtained which are notquite free of pores or not completely homogenous or do not cover therims well, preferably a larger thickness of the barrier layer isselected. When high topographic steps are present on the layeredstructure, a layer thickness of up to approximately 2 mm is selected fora good edge covering of the barrier layer.

By the addition of the polymeric polyol to the curable resin,particularly the film forming properties of the curable resin areimproved. Moreover, PVB layers or other polymeric polyol layers are veryoften used as lamination layers during the assembly of components orduring the manufacture of solar cells. Such barrier layers form aparticularly close connection to the barrier layer made of polymericpolyol containing curable resin, since they excellently couple to thepolymeric polyol within the curable resin.

The barrier layer is formed as a barrier layer for protection againstmoisture and is located at least at one outer surface of the component,which outer surface is the outer surface of the layered structure and atleast part of the surface of the substrate that is not covered by thelayered structure.

With such a barrier layer made of a curable resin containing polymericpolyol for example thin film solar modules can be constructed which passthe damp-heat climate test mentioned at the beginning with a performanceloss of less than 5% and without visible corrosion damage.

Since the barrier layer according to the present invention adapts to thefunction of the covered layered structure and, for example, is opticallytransparent or electrically insulating, it shows no negative influenceto the layered structure. Neither does it affect the operation of anoptical or electrical component that is incorporated in the layeredstructure nor does it impair the properties thereof.

The barrier layer demonstrates good adhesion on most materials that areused as an electrical or optical function layer or the substrate.Possibly an additional adhesion providing layer may be necessary.

Since a layered structure can comprise the barrier layer as anadditional layer to the conventional layered structure comprising one orany number of layers, it can further be covered with a conventionalcovering, for example with a laminate. Thus, a laminate consisting of aglass plate and an intermediate adhesive layer can also be provided ontop of the barrier layer covering the layered structure. Othercomponents can additionally or alternatively be covered with orenveloped in cast resin layers or other casting compounds on top of thebarrier layer.

The barrier layer according to the invention is especially suitable forapplying a laminate covering it, as it demonstrates good adhesion on orunder conventional hot melt adhesive layers, used therefore. Thisresults from the close connection between polymeric polyol and laminate.The good adhesion of the hot melt adhesive film, and hence of the entirelaminate structure, results in an additional improved impermeability,which prevents diffusion of moisture along the interfaces betweenlayered structure and laminate or between barrier layer and laminate,respectively.

Preferably the barrier layer encloses the layered structure that issensitive to moisture from above and from the side and ends at the loweredge on the substrate that for example consists of glass. The barrierlayer according to the present invention can also cover a metal layer ora passivation layer. The passivation layer can also be an inorganicbarrier layer. Suitable materials for a passivation layer are siliconoxide, titanium nitride and molybdenum nitride. The latter two areparticularly hard and scratch resistant as well. The barrier layer ofthe present invention demonstrates good adhesion to all the layers andthus form moisture-impermeable and chemically stable interfaces to theselayers.

In one embodiment of the invention the layered structure is anelectrical component having at least two electrodes wherein oneelectrode is formed by an electrode layer located directly on thesubstrate. This electrode is called a back electrode, and the backelectrode can be structured, to obtain an electrode structure that isparticularly suitable for integrated series connected thin film solarmodules.

In addition to the necessary electrode structure also the electricalconnections for the at least two electrodes can be formed from this backelectrode layer and led out of the component region laterally. Such anarrangement has the advantage that it can be formed particularly flatwithout additional structure steps, as opposed to a conventionalarrangement with, for example, electrical connections soldered on. Thisfacilitates an edge covering envelopment with the barrier layeraccording to the invention.

The electrical connections led out of the layered structure of thecomponent under the barrier layer and formed from the first electrodelayer can consist of a corrosion resistant metal. Preferably, however,they are covered by an electrical conductive passivation layer, inparticular a titanium nitride or a molybdenum nitride layer. Thepassivation layer can completely cover the lower electrode layer and bestructured in accordance therewith. It is also possible to cover thelower electrode layer with passivation layer exclusively in the regionof the electrical connections, and in particular only in the area of thelead through the connections under the barrier layer.

Another advantageous embodiment of the invention relates to the alreadymentioned CIS thin film solar modules. As known, for example, from theGerman patent No. DE 44 42 824 C1, a defined alkali content in the CISabsorber layer is necessary for a maximum efficiency of the solar cell.Since with the use of a glass substrate a defined alkali content of theCIS absorber layer can only be achieved with an alkali barrier layerdirectly above the glass substrate or above the back electrode layer, abarrier layer according to the invention, formed as a passivating layerabove the back electrode can be used for such a barrier layer in afavourable manner. Simultaneously, a barrier layer made of titanium ormolybdenum nitride can serve as a passivation layer for the electricalconnections leading to the outside, or as a barrier layer for the entirelower electrode, respectively. It exhibits particularly good adhesion toan additional barrier layer above the solar cell and forms aparticularly good and impermeable interface to the barrier layertherewith.

The invention will now further be described by way of example withreference to some experiments. In order to get reproducible resultsApplicant has carried out the damp-heat test on a special componentcomprising a glass substrate on which doped electrode zinc oxide hasbeen deposited by means of chemical vapour deposition. The testcomponents were equipped with electrodes, and the sheet resistance wasmeasured. In order to achieve a fill factor with solar modules, however,a lower value is necessary.

Reference is now made to FIG. 4 showing schematically a cross-section ofthe test component. On a substrate 20 of a 2 mm thick window glass platesoda lime glass (having a length of 10 cm and a width of 10 cm) a borondoped zinc oxide layer 21 having a thickness of 1.5 micrometre isapplied by means of chemical vapour deposition. After application of thezinc oxide layer, strips of zinc oxide of 10 mm width are removed fromthe substrate 20, so as to make four uncovered rims of which rims 23 and24 are shown in FIG. 4. Then two metallic contact strips (not shown) arejoined to the zinc oxide layer on opposite sides thereof, so that thesheet resistance of the zinc oxide layer can be determined reliably.

Having applied the contact strips, a barrier layer 26 was applied, aswill be discussed below. Thereafter a glass cover 28 was adhered to thebarrier layer by means of an adhesive layer of polyvinyl butyral 29. Theadhesive layer 29, having a thickness of 0.5 mm, was allowed to setunder 145° C. for 30 minutes under pressure. The pressure was applied onthe glass cover 28 by means of a membrane (not shown) separating avacuum chamber (with the component in it) and a pressurized chamber, andthe pressure difference over the membrane was 450 millibar.

In order to show the effectiveness of the barrier layer according to theinvention four experiments were carried out to determine the sheetresistance of a zinc oxide layer under the damp-heat test. In this testthe modules are exposed to a temperature of 85° C. at 85% relative airhumidity for 1 000 hours.

The barrier layer according to the present invention was prepared asfollows. First a liquid resin composition was prepared. The liquid resincomposition consisted of: 35 g polyvinyl butyral, 357 g cycloaliphaticepoxy resin, 236 g OH-134, consisting of bisphenol A and cycloaliphaticepoxy resin Araldit CY 179 in the proportion of 1:3, 157 g epoxidizedsoy bean oil, 197 g trifunctional polyester polyol, 9.8 gtriarylsulphonium hexafluoroantimonate, 3.9 g(3-glycidoxypropyl)-trimethoxysilane, 3.4 g dimethylpolysiloxanederivative.

Then the liquid resin composition was brushed over the component so asto cover the zinc oxide layer and the rims 23 and 24 around the zincoxide layer. And under UV conditions, the resin composition was allowedto harden.

Then the electric connections were made (not shown) to the metalliccontact strips (not shown) and the test component was put in a containerfor the damp-heat test. During the test the sheet resistance wasmeasured.

In order to compare the obtained result, comparative experiments wereconducted. At first, the component was not covered with a barrier layer.

Then two comparative experiments were conducted with barrier layersconsisting of a conventional resin. In the first comparative experiment,the barrier layer was made using a liquid resin composition consistingof a two-component lacquer 1640 (from RhenatechElektroisoliersysteme)—comparative example A. And in the secondcomparative experiment, the barrier layer was made using a liquidUV-curable acrylate resin composition Multi-Cure 984 (Trade name) LVUF(from Dymax Europe GmbH)—comparative example B.

The resin compositions were brushed on test components as discussed withreference to the composition according to the invention and allowed toharden.

Then the sheet resistance of the three test components were measuredunder the same conditions as the sheet resistance of the componentaccording to the invention was measured. The sheet resistances werenormalized so that the initial sheet resistance was 1 for allcomponents.

The results are shown in the below Table.

TABLE Normalized sheet resistances measured of zinc oxide measured withthe barrier layer according to the invention and three comparativeexamples. According No Time to the barrier Comparative Comparative(hours) invention layer example A example B 0 1.0 1.0 1.0 1.0 200 1.01.7 1.1 1.0 400 1.1 3.0 1.7 1.2 600 1.4 4.1 2.5 1.4 800 1.5 4.8 3.2 2.01000 1.8 5.7 4.2 2.9

The Table shows the improvement obtained with the barrier layeraccording to the present invention.

With the invention, the climate and corrosion stable encapsulation ofany layered structure and in particular thin film arrangements with alarge surface, which comprise climate and corrosion sensitive layers,can successfully be done. The invention is particularly suitable forsuch thin film arrangements that are exposed to hot and/or humidenvironments, such as solar cells. Of course this is also valid forlayered structures that are usually not exposed to such corrosionpromoting environmental conditions.

1. A component comprising a substrate, a layered structure arranged onthe substrate, and a barrier layer arranged over the layered structurefor protection against moisture, wherein the layered structure includesan optically active film and wherein the barrier layer comprises thereaction product of polymeric polyol in the form of polyvinyl butyral,and a curable epoxy resin, wherein the amount of polymeric polyol is inthe range of from 1% to 30% by weight of the curable epoxy resin.
 2. Thecomponent of claim 1, wherein the barrier layer is located at least atone outer surface of the component.
 3. The component of claim 2, whereinthe layered structure comprises an edge at its outer surface and whereinthe barrier layer covers the edge.
 4. The component of claim 1, whereinthe barrier layer is impermeable to moisture.
 5. The component of claim4, wherein the layered structure comprises an edge at its outer surfaceand wherein the barrier layer covers the edge.
 6. The component of claim1, wherein the component further comprises a laminate structure with acover and an intermediate adhesive layer that is arranged over thebarrier layer.
 7. The component of claim 6, wherein the cover comprisesat least one plastic layer.
 8. The component of claim 6, wherein thecover is a glass plate.
 9. The component of claim 6, wherein theintermediate adhesive layer consists of polyvinyl butyral.
 10. Thecomponent of claim 1, wherein the curable epoxy resin is UV curable. 11.The component of claim 1, wherein the barrier layer covers the layeredstructure on a top surface facing away from the substrate and on a side,and ends on the substrate.
 12. The component of claim 1, which componentis a solar cell or a solar module.
 13. The component of claim 1, whereinthe layered structure comprises a moisture-sensitive absorber layer. 14.The component of claim 13, wherein the moisture-sensitive absorber layercomprises copper-indium-diselenide.
 15. A solar cell comprising asubstrate, a layered structure arranged on the substrate, and a barrierlayer arranged over the layered structure for protection againstmoisture, wherein the barrier layer comprises the reaction product of apolymeric polyol and an epoxy resin, and wherein the amount of polymericpolyol is in the range of from 1% to 30% by weight of the epoxy resin.16. The solar cell of claim 15, wherein the wherein the layeredstructure includes an optically active film.
 17. The solar cell of claim16, wherein the optically active film comprises a moisture-sensitiveabsorber layer.
 18. The solar cell of claim 17, wherein themoisture-sensitive absorber layer comprises copper-indium-diselenide.19. The solar cell of claim 15, wherein the polymeric polyol comprisespolyvinyl butyral.
 20. The solar cell of claim 15, further comprising acover and an intermediate adhesive layer that is arranged over thebarrier layer.
 21. A solar module comprising a substrate, a layeredstructure arranged on the substrate, and a barrier layer arranged overthe layered structure for protection against moisture, wherein thebarrier layer comprises the reaction product of a polymeric polyol andan epoxy resin, and wherein the amount of polymeric polyol is in therange of from 1% to 30% by weight of the epoxy resin.